<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<!--内部内部优先级最高
    内部和外部优先级相同  后执行的覆盖之前执行的-->
   <style type="text/css">
     span{
      color:green;
     }
     </style>
     <link rel="stylesheet" href="first.css">
</head>
<body>
	<div>div1</div>
	<div style="color:red">div2</div>
	<div>div3</div>
	<span>span1</span>
	<span>span2</span>
	<span>span3</span>
	<h3>aaa</h3>
	<h3>bbb</h3>
</body>
</html>